1. Field of the Invention
The present invention relates to probes useful in endoscopy and other procedures, and more particularly to balloon probes adapted to obtain spectroscopic information in the infrared spectral region. The invention also relates to methods that utilize these probes to analyze a surface of interest in connection with the diagnosis and treatment of disease.
2. Description of the Background
Numerous minimally-invasive diagnostic and treatment devices and methods of using them have been developed. Two such categories of devices are endoscopes and balloon catheters.
Endoscopes have proved useful in the examination of internal surfaces, in connection with various surgical and diagnostic procedures. However, conventional endoscopes, such as colonoscopes, gastroscopes, bronchoscopes, and angioscopes, are limited in their ability to detect all pathology present or provide unequivocal identification of abnormalities. These devices typically collect reflected visible light from a lumen, which may be expanded with water or gas, for simple visual evaluation of the tissue surface of interest. If a definitive diagnosis of the type of pathology or disease present in the tissue is needed, a tissue specimen is typically removed or biopsied and submitted for pathologic testing. Unfortunately, the biopsy process increases the risk of complications to the patient, such as hemorrhage, infection, and possible perforation of the organ or vessel under examination.
In addition to endoscopic devices that collect reflected visible light to produce an image allowing for simple visual evaluation, endoscopes that detect fluorescence emitted following excitation of tissue with a radiation source have also been described. One such device includes a visible light source, an optional endoscopic probe, optical sensors, a filter, a detector, and a display monitor. One or two wavelengths of visible light, preferably blue and red/near-infrared light, is directed to the tissue of interest, and remittance and autofluorescence is then detected, integrated/processed and displayed (U.S. Pat. No. 5,590,660 to MacAulay). This device does not incorporate balloons into the probes to facilitate optical coupling, to allow infrared-based evaluation of the diseased tissue.
Another device, useful for diagnosing the condition of GI tissue, utilizes fiber optics to detect emitted fluorescence following excitation radiation treatment (U.S. Pat. No. 5,421,337 to Richards-Kortum). In addition, devices which detect precancerous lesions using a mercury arc lamp endoscope (U.S. Pat. No. 5,647,368 to Zeng), devices which monitor and determine pre-existing physical properties of an organ by excitation with UV light (U.S. Pat. No. 5,456,252 to Vari), and devices which determine bilirubin concentration in tissue using reflectance spectroscopy (U.S. Pat. No. 5,353,790 to Jacques) have also been described. However, these devices do not combine balloon endoscopes with infrared radiation to detect diseased tissue.
Balloon catheters, like endoscopes, have been routinely used for diagnostics and treatment. Typical uses of conventional balloon catheters include procedures such as angioplasty and embolectomy. However, prior to the present invention, these conventional balloon devices could not be used in procedures in which infrared light is emitted in close proximity or directly onto a tissue surface, followed by collection of the light reflected or emitted from the tissue of interest, due to moisture and fluids in the surrounding environment.
The use of infrared radiation in catheters and endoscopic devices is complicated by the fact that water and most bodily fluids are opaque to infrared light. Consequently, even the slightest amount of moisture on the collection end of an endoscopic probe impairs the collection of infrared light. As a result, conventional endoscopes and balloon catheters cannot be used in infrared procedures where moisture or bodily fluids are present.
Fiber optic laser catheters and endoscopes having a protective shield over the probe tip have been described as useful in connection with the diagnosis and removal of atherosclerosis. In one such device, an optical fiber(s) carrying laser radiation is mounted in a catheter having a transparent protective optical shield over its distal end (U.S. Pat. Nos. 5,318,024 and 5,125,404 to Kittrell). The fiber(s) is anchored within the catheter so that there is an appropriate distance or space between the output end of the fiber(s) and the tip of the shield. The intervening space may be filled with fluid, optical surfaces may be optically contacted, or they may be anti-reflection coated to reduce reflections and maximize transmitted light. The catheter may be inserted into a blood vessel and the shield brought into contact with a plaque or obstruction site.
In this device, the protective optical shield mechanically displaces blood at the region to be analyzed and also protects the distal tip of the optical fiber(s) from intra-arterial contents. By locally displacing blood, the shield allows viewing of the tissue of interest without the need for a purge or flush. The optical shield may be in the form of glass, fused silica, sapphire or other optically transparent material. A flexible balloon over the tip of the probe may also be used as an optical shield. A different balloon may be used to provide an anchor point for positioning the catheter during use.
Although the shields of these devices protect a probe tip from blood contaminants, the use of a single balloon to both anchor and protect the tip of the probe from infrared opaque contaminants, which simultaneously allows optical coupling in the infrared region between the probe tip and the tissue surface has not previously been described. The Kittrel devices are designed for use with visible light. In addition, probes incorporating two anchoring balloons which allow the evacuation of a lumen and its subsequent filling with an infrared lucent coupling fluid are also not described.
As can be seen, because of the challenges posed by the effect of moisture on infrared light transmission, available endoscopic devices and catheters are limited in their ability to access and evaluate tissue and/or the lumen of vessels and organs using infrared light. There is therefore a need for a relatively non-invasive device which allows for optical coupling of a probe to the tissue or surface of interest, thereby allowing thorough evaluation and diagnosis of tissues and/or the lumen of vessels and organs using infrared radiation.
The invention overcomes the problems and disadvantages associated with current strategies and designs and provides new devices and methods for obtaining diagnostic information through the use of endoscopic balloon probes, particularly those utilizing infrared (IR) spectroscopy.
Probes according to a preferred embodiment of the present invention include an IR-transmitting single or multiple fiber endoscope, which is connected to a high resolution spectrometer. Infrared spectra are collected and used for diagnosis. The use of spectroscopy with a fiberoptic endoscope allows the collection of high resolution information in the infrared spectral region from diseased tissue. The present invention allows for rapid and accurate analysis of an organ, despite the presence of moisture, without the need for a tissue biopsy and its potential complications, such as hemorrhage, perforation and infection. In addition, by using the anchoring balloons in conjunction with the endoscopic probes, collection of diagnostic spectra, particularly infrared radiation, in the lumen of a vessel or organ is even further enhanced. The novel balloon configurations displace any opaque fluids which may be present and allow optical coupling of the probe to the tissue of interest.
In addition, multiple fibers may be paired with hyperspectral imaging techniques. Each fiber""s data may be processed to provide a single pixel. The pixels produced by each individual fiber may be incorporated into an imaging array and/or translated into an image or other display optimized so that it may be readily interpreted or read by the user.
Accordingly, one embodiment of the invention is directed to a probe device which is useful for collecting infrared radiation from a surface of interest. The collected radiation is analyzed to provide information about the tissue surface. The probe device of this embodiment comprises a collection fiber which has a proximal end, a distal collection end opposite the proximal end adapted to collect infrared radiation, and an infrared conductive core located between the proximal end and the distal collection end. A sheath surrounds a portion of the collection fiber. A first anchoring balloon is preferably disposed on the sheath. The distal collection end of the collection fiber may be nested inside or disposed inside the balloon. This configuration displaces the opaque fluids which may be present, optically couples the probe to the tissue when the balloon is inflated, and protects the collection end of the probe from contamination.
Alternately, the first anchoring balloon may be disposed on the sheath between the proximal end and the distal collection end of the fiber and a second anchoring balloon may be disposed on a portion of the sheath that extends distally past the distal collection end of the collection fiber. When the two balloons are inflated, the void created between the balloons and the lumen wall may be filled with an infrared lucent fluid, displacing any infrared opaque fluids. This allows optical coupling of the collection end of the probe to the tissue surface, and protects the end of the probe from contamination.
Another embodiment is directed to a probe device having a plurality of collection fibers adapted to collect light, which is preferably infrared light. The probe device of this embodiment comprises an imaging collection fiber bundle comprising a plurality of collection fibers, each of the plurality of collection fibers comprising a proximal end, a distal collection end opposite the proximal end, and a conductive core located between the proximal end and the distal collection end. A first anchoring balloon is disposed on the fiber bundle; preferably it is disposed so that the distal collection ends of the plurality of collection fibers are disposed inside the balloon. Alternately, it may have the two balloon configuration previously described.
Another embodiment is directed to an endoscopic probe having a collection fiber which has a proximal end, a distal collection end opposite the proximal end adapted to collect infrared light, and a conductive core located between the proximal end and the collection end. The probe also has an illumination fiber having a distal illumination end adjacent the distal collection end of the collection fiber, and a proximate end coupled to the illumination source. An infrared lucent anchoring balloon is positioned on the probe such that the distal collection end of the collection fiber and the illumination end of the illumination fiber is disposed in the balloon. The illumination fiber preferably provides infrared light.
Another embodiment of the invention is directed to an endoscopic probe comprising a toroidally-shaped anchoring balloon, having a central hole or bore therethrough, and a collection fiber adapted to collect infrared radiation. The fiber has a distal collection end disposed inside the central hole of the balloon.
The present invention is also directed to methods for obtaining information about a surface of interest. One such method comprises the steps of positioning a probe adjacent to the surface of interest, collecting infrared light using the probe, transmitting the infrared light from the surface to analyzing means, and analyzing the infrared light to determine one or more properties of the surface. In this embodiment, the probe preferably comprises a collection fiber, the collection fiber comprising a proximal end, a distal collection end opposite the proximal end adapted to collect infrared light, and an infrared conductive core located between the proximal end and the distal collection end, and at least one anchoring balloon disposed on the probe.
Another embodiment is directed to a method for obtaining information about a surface of interest, comprising the steps of positioning a probe adjacent to the surface of interest, collecting infrared light using the probe, transmitting the infrared light from the surface to analyzing means, and analyzing the light to determine one or more properties of the surface. In this embodiment, the probe preferably comprises a light collection fiber bundle comprising a plurality of collection fibers adapted to collect infrared light, each of the plurality of collection fibers having a proximal end, a distal collection end opposite the proximal end, and a conductive core located between the proximal end and the distal collection end. A first balloon may be positioned on a sheath between the proximal end and the collection end of the plurality of collection fibers and a second balloon disposed on the sheath distal to the collection ends. Alternately, a balloon may be disposed on the probe such that the distal collection ends of the fibers lie inside the balloon.
Still another embodiment is directed to a method for obtaining information about a tissue surface, comprising the steps of collecting infrared radiation from the tissue surface using a probe placed proximate to the tissue surface, the probe having a longitudinal axis, transmitting the infrared radiation from the tissue surface to a remote analyzer, and analyzing the infrared information to determine properties of the tissue. The remote analyzer may comprise a spectrometer and detector array.
Although preferred embodiments of the invention are directed to probes having fibers and optical coupling means uniquely suited for the collection and analysis of infrared wavelengths, as will be clear to those of skill in the art, in other embodiments, additional fibers may be incorporated into the probes, so that other wavelengths (in addition to infrared) may be collected and analyzed.
Other objects and advantages of the invention are set forth in part in the description which follows, and in part, will be obvious from this description, or may be learned from the practice of the invention.